Axial-flow air-moving devices



Oct. 22, 168

AXIAL-FLOW AIR-MOVING DEVI CES Filed July 12, 1966 2 Sheets-Sheet l 's. E. v. BOOTH 3,406,898

Oct. 22, 1968 s. E. v BOOTH 3,406,898

AXIAL-FLOW AIR-MOVING DEVICES Filed July 12, 1966 2 Sheets-Sheet 2 204 250 F/&. u

United States Patent 3,406,898 AXIAL-FLOW AIR-MOVING DEVICES Septimus E. V. Booth, deceased, late of Wokingham, England, by Gillian H. Booth, sole administratrix, Field House, Langley Common Road, Barkham, Wokingham, Berkshire, England Filed July 12, 1966, Ser. No. 564,563 Claims priority, application Great Britain, July 13, 1965, 29,725/65 15 Claims. (Cl. 230-270) ABSTRACT OF THE DISCLOSURE A fan or other axial-flow fluid-moving device having blades with adjustable pitch and means responsive to the temperature of the fluid flowing through the device for controlling the pitch.

An object of the invention is to provide an axial-flow fluid-moving device comprising simple and nevertheless efliective means for adjusting the pitch of the blades.

Another object of the invention is to provide an axialflow fluid-moving device having a hub comprising two parts which are axially displaceable relative to each other and which are connected with the blades of the device by means simultaneously serving as supporting means for the blades and as means for providing for adjustment of the pitch thereof.

A further object of the invention is to provide a fan to be used with automobile engines and other fluid cooled internal combustion engines, which fan is by simple and cheap means adapted both simply and economically to have the pitch of the blades adjusted in accordance with the temperature of the cooling fluid in such a manner that the pitch is at a minimum and thereby the power consumption of the fan at a minimum when the cooling water is cold and until the temperature of said water rises above a predetermined value, so that the fan is effective only at temperatures of the cooling fluid above the normal or prescribed working temperature.

Three embodiments of the invention will now be described, by way of example, with reference to the accompanying drawings which illustrate axial-flow fans in accordance with the invention and in which:

FIG. 1 is a fragmentary side elevational view of a blade mounted between two plates;

FIG. 2 is a plane view of a blade;

FIG. 3 is a section on the line 3-3 of FIG. 2 with the blade in fine pitch;

FIG. 4 is a section on the line 3-3 of FIG. 2 with the blade in coarse pitch;

FIG. 5 is a section on the line 55 of FIG. 2;

FIG. 6 is a section on the line 6-6 of FIG. 5;

FIG. 7 is a fragmentary perspective view of a blade in fine pitch corresponding to FIG. 3;

FIG. 8 is a fragmentary perspective view of a blade in coarse pitch corresponding to FIG. 4;

FIG. 9 is a similar view to FIG. 4 showing a modification of the invention;

FIG. 10 is a radial section through one blade and mounting parts therefor according to a third embodiment of the invention;

FIG. 11 is a side elevation of the root part of the blade;

3,406,898 Patented Oct. 22, 1968 FIGS. 12 and 13 are, respectively, end and side elevations of a bearing member;

FIGS. 14 and 15 are, respectively, end and side elevations of tongues cooperable with the bearing members, and

FIG. 16 is a section on line 1616 of FIG. 10.

Referring to the drawings, FIG. 1 shows one'blade 10 of a fan having a plurality of radially-disposed blades mounted between two plates 11 and 12 together forming a hub and mounted on a shaft (not shown) in such manner as to be relatively movable bothaxially and rotationally of the shaft. The plates are of polygonal shape in the described embodiment but they could be circular, and they are mounted in spaced parallel relationship. The plates are relatively movable to vary the distance between them and to vary their rotational relationship.

The plate 11 has a flange 13 around its perimeter and plate 12 has a similar flange 14, said flanges being directed one towards the other and being shaped so as to allow the blade root to pass between them at any angle of pitch between prescribed limits.

In the root of each blade at two transversely-spaced locations are two seats holding captive balls 15, 16 each having slots 17 therein. On the flanges 13, 14 are barbed tongues 18, 19 which serve as pivot means for the blade 10 and engage in the slots 17 in the balls 15, 16 respectively which serve as bearing members.

A plate 20 (see FIGS. 5 and 6) engages flexibly in slits 30 in the blade 10 and abuts lightly against the inside surface of the flanges 13 and 14.

In the present embodiment the blade 10 may be made of polypropylene, the plates 11 and 12 may be made of steel, the balls 15 and 16 may be made of nylon and the plate 20 may be made of nylon or polyvinyl chloride.

To alter the pitch of the blades 10, the plate 11 is moved towards or away from plate 12 and rotated slightly relative thereto. The balls are thus rotated in their seats and the pitch of the blades is consequently altered. The blade is shown in fine pitch in FIG. 3 with the plates 11, 12 close together, and in coarse pitch in FIG. 4 with the plates 11, 12 moved apart. Temperature-responsive means of known construction may be disposed between the plates 11 and 12 mounting each blade 10 and be coupled to the plates in order automatically to vary the pitch of the blades in accordance with variation in the ambient temperature.

The plate 20 occludes air from circulation through and around the blade root and also acts as resilient means to restrain the blade from swinging freely on its ball joints, but allowing the blade to take up a position under the influence of the centrifugal force and the air load so that minimal blade-root bending moments are generated.

Referring now to FIG. 9 there is shown a second embodiment of the invention in which parts are indicated by reference numerals increased by over those used for like parts in FIGS. 1 to 8. Tongues 118 and 119 are formed integrally with plates 111 and 112, no flanges being present. Each tongue is cut and bent out from the edge of one of the plates. N0 plate such as plate 20 is provided in this embodiment, but plates 111 and 112 are set close together and there is thus little space for undue recirculation of fluid around the roots.

In FIGS. 10 to 15 illustrating a third embodiment of the invention, parts already described are indicated by reference numerals increased by 200 over those used for like arts in= FIGS. 1. to

8tln this embodiment there is shown the shaft 201 on which the hub is mounted. The shaft 201 has an end flange 202 on which the plate 212 on the hub is secured by bolts 230 and cooperating nuts 231. There is also shown, disposed between the plates, temperature-responsive means comprising a thermostat 215 from whose end 232 remote from plate 212 extends a feeler 216 which passes through an opening 233 therefor in the plate 211 and ,through a cage 234 to atmosphere there to be subject to the ambient temperature. The cage 234 mounts a seat 220 for a spring 239 serving to urge the plate 211 towards the plate 212 in opposition to the thermostat 215. The spring 229 is rated to coact with the thermostat in varying the inter-plate spacing in response to changes in the ambient temperature. The cage 234 is made up of an end disc 235 through a central opening 237 in which the feeler 216 passes and rods 217 which pass through openings 236 therefor in the plate 211 and are secured to the plate 212. p

This embodiment of the invention differs from.those already described in the blade-mountin'g arrangement. In this embodiment, the tongues 218 and 219 extend radially of the axis of the shaft 201 and each has a notch 203 in its'outer side edge at a short distance from its radial edge 237. Said radial edge 237 is foreshortened by a length slightly greater than the depth of the notch 203 and is reversely bent to provide a barb 204 which does not extend as far as the base of the slot in the radial direction. A roller-shaped bearing member 207 of resilient material has therein a slot 205 which corresponds in shape to the barb and part of the tongue 218 or 219 from which it extends so that the bearing member can be snapfitted to the tongue. The bearing member 207 is partspherical at its inner end 213.

Each of the blades 210 has two-transversely-spaced rectangular bearing slots 209 and 249 in the root thereof, and, below the slots and between same and inner edge of the blade is locally thickened at both sides to provide cylindrical seating members 208 and 248 having partspherical dished outer surfaces 250 and 251 facing the slots.

In mounting the blades 210, the bearing members 207 are snap-fitted on to the tongues and are then fitted to the blades, firstly by engaging the notches 203 on the blades at the upper ends of the bearing slots and then pressing the bearing members into the position wherein their part-spherical inner ends 213 seat in the part-spherical dished outer surfaces 250 and 251 of the seating members 208 and 248.

In a modification of the invention the plates 11 and 12, or 111 and 112, or 211 and 212, are fixed relative to one another, whereby the fan is a fixed pitch fan.

It will be manifest that the invention is applicable to axial-flow fluid-moving devices other than fans, for example, it is applicable to turbines.

Among the advantages of the invention are that it provides axial-flow fluid-moving devices enabling hinging movements of the blades or vanes which obviates a common cause of failure due to bending moments at the roots of the blades or vanes.

Among the further advantages of devices according to the invention are that they can be cheap; easy to operate; require little or no maintenance or lubrication; and have an intrinsically reliable structure. Devices like those described as the first embodiment are also aerodynamically efficient as air is prevented from recirculating at the blade or vane root.

I claim:

1. An axial-flow fluid-moving device comprising:

(a) a hub;

(b) a plurality of blades; and

(0) two swivel joints connecting each blade to the hub to extend radially therefrom and to rotate therewith, the centres of which joints are at fixed positions relative to said blade and are spaced apart circumferentially relative to said hub; each said blade being free to move about an axis extending between the centres of said two joints.

2. A device as set forth in claim 1, wherein said blades are movable relative to each other on the hub axis and are relatively rotatable on the hub axis.

3. A divice as set forth in claim 2, and further comprising temperature-responsive means adapted to effect said relative axial movement.

4. A device as set forth in claim 3, comprising:

(a) a shaft;

(b)- said hub consisting of twoparts, v s

(c) means mountingsaid parts on said shaft in spacedapart relationship to define a space and in such manner as to be relatively movable bothaxially and rotationally of said shaft;

(d) circumferentially-spaced tongues on each said part extending in the direction of the other said part, the tongues of one said part being offset circumferentially to the tongues of the other said part to provide pairs? of oppositely directed tongues in;said space;

(e). fan blades disposed radially of said hub and each having a root entering said space; and

(f) means at two transversely-spaced locations on each said root engaged by and cooperable with a said pair of tongues to permit rotational displacement'of the appertaining blade about two axes at each said location.

5. A device as set forth in claim 4, wherein said parts are substantially flat plates mounted in parallel relationship and each tongue is formed by a portion of one plate, said portion being cut and bent out from the edge of said plate to extend perpendicular to the plane of the plate.

6. A device as set forth in claim'5, in which each blade root has two transversely-spaced openings therein and is locally thickened radially inwards of said openings, each said local thickening being shaped to present to the appertaining opening a part-spherical seating surface; and in which each said swivel joint comprises a bearing member entered into a said opening 'to be captive therein and seating on the seat presented to said opening and means mounting said bearing member on a said tongue.

7. A device as set forth in'claim 5, in which each swivel joint comprises a ball, means on a said root holding said ball captive against axial displacement but free to rotate, said ball having a slot therein, and a said tongue engaged in said slot.

8. A device as set forth in claim'7, including means resiliently restraining the blades from swinging and preventing air recirculating around said roots.

9. A device as set forth in claim 8, wherein said means comprise a plate secured to each said root, each plate extending in a plane perpendicular to the long axis of its associated blade, and wherein said two parts each have peripheral flanges extending towards one another and having inner faces, said plates being disposed to engage said inner faces.

10. An axial-flow fluid-moving device comprising a hub rotatable about an axis, the hub comprising two parts extending radially of said axis with a space therebetween, said parts having limited relative movement both axially and circumferentially, each of said parts having a tongue extending toward the other part in said space, the tongues being circumferentially offset relatively to each other, a blade, and bearing members interconnecting the blade with said tongues respectively, said members being rotatably mounted in the blade and the blade being supported on said hub parts solely by said members.

11. A device according to claim 1 wherein the offset of said tongues is substantially 12. A device according to claim 1 wherein said bearing members have spherical surfaces.

13. A device according to claim 1 wherein the inner 5 6 end of each bearing member is spherical and seats in a References Cited spherical cup in the blade, each bearing member has 21 UNITED STATES PATENTS slot to receive said tongue, and the outer end of each 1,279,742 9/1918 Mott 170*160'39 bearing member having a notch to receive an edge of the r 2,284938 6/1942 Allen 230 114 hub. 0 2,417,917 3/1947 Everts 170-160.39

. 14. A dev ce accordlng to cla m 13 wherein the blade FOREIGN PATENTS is made of yielding plastic material.

15. A device according to claim 1 further character- 620296 5/1961 Canada ized by temperature-responsive means for producing said 10 HENRY R RADUAZO, Primary Exam-"en axial movement. 

